import { HumanMessage, isHumanMessage } from "@langchain/core/messages";
const msg = new HumanMessage({
  content: [
    { type: "text", text: "请描述这张图片" },
    { type: "image_url", image_url: "https://example.com/cat.png" },
  ],
});

console.log(isHumanMessage(msg));
